What is the shear modulus of viton material?

i am new to rubber components , now i am developing a bladder for pulsation dampener, so for that i need to check the spring rate or elasticity of viton material and to determine the thickness for the bladder, I am struggling a lot to find the shear modulus of rubber, if have this valve i have basic formula to find out the thickness and deflection. So i request all the experts present in this group to help me out to get this shear modulus value of viton.